ABSTRACT
Light olefins will play a dominant role in any future methanol-based chemicals economy. Olefins are initial products in the conversion of methanol to hydrocarbons over zeolite catalysts. This chapter shows that a wide variety of methods is available for increasing total olefin selectivity from methanol conversion. Light olefins are the major products of methanol conversion in the presence of small pore zeolites, i.e., those with pore openings defined by 8-rings of oxygen atoms. Olefin selectivity is increased at high temperature. A kinetic analysis of the interrelation between temperature and catalyst activity has been made with ZSM-5. The chapter contains detailed selectivity data for conversion of dimethyl ether over P-modified ZSM-5 at various temperatures. W. E. Garwood found that olefins equilibrate rapidly in the presence of ZSM-5, yielding mixtures whose composition is largely governed by thermodynamics. The methanol reaction differs from Garwood's reaction, which is conducted in the absence of water.
